JSFiddle - React, Tailwind, and code Playground

HTML

<div class="hoverBox">Mouse hover <span>Hello</span></div>

CSS

.hoverBox span {
  opacity: 0;  
  transition: opacity 0.5s;
  transition-delay:2s;
}
.hoverBox:hover span {
  opacity: 1;  
  transition-delay:0s;
}